Hello and welcome to live coverage of stage 20 of the Tour de France - the all-important 22.5km individual time trial in Marseille, where the destiny of the yellow jersey will finally be decided...

World TT champion Tony Martin will be rolling down the ramp in seven minutes: the German from Katusha-Alpecin will be one of the favourites to win today, along with the likes of Chris Froome and Primoz Roglic...

The man who wore the Tour's first polka dot jersey is the man who leads this Marseille ITT: Phinney is still the man to beat, 50 seconds ahead of Albert Timmer.

The big guns won't be rolling down the ramp in the Orange Velodrome until much later today - these times are in CEST, so Chris Froome will be starting his quest for a fourth Tour win at 16:04 BST.

Earlier, Dutchwoman Annemiek Van Vleuten (Orica-Scott) followed up her victory on the Col d'Izoard with victory in the "chase" time trial for part two of La Course. She won the experimental pursuit by 1:52 over Lizzie Deignan of Great Britain, with Italy's Elisa Longon Borghini coming third another second back.

Phinney kept his form all the way to the end - and he has set the best time at the finish: 29min 21sec is his reference - 50 seconds quicker than second-placed Alberto Timmer of Team Subweb.

It's quite a location for the start and finish - the Orange Velodrome. And Rowe is the first rider to complete the course, coming home in a time of 31min 9sec.

British champion Steve Cummings is the latest rider to roll down the ramp. He hasn't been able to win a stage in this year's Tour - as he did for the previous two years - and he's unlikely to do so today or tomorrow. But you never know...

Here's Phinney tackling that tough climb to Notre Dame, atop of which he also set the best time at the second check. His target is 21:13 which is 55 seconds quicker than Wagner, which goes to show how big the time gaps could potentially be today in this short, but sharp, race against the clock.

As it stands, Taylor Phinney (Cannondale-Drapac) has set the fastest time at the first checkpoint at the Palais du Pharo after 10.2km. The American's target time is 12:26 - which is 19 seconds quicker than Robert Wagner of LottoNL-Jumbo. 14 riders have gone through.

And here's Luke Rowe grappling with that climb...

Here's a video of today's course, which takes the riders along the sea front of Marseille en route to a finish in the Stade Velodrome where Olympique Marseilles play their home games.

The first riders are already on the course, with Luke Rowe of Team Sky getting this decisive time trial under way. The Welshman is approaching the climb so we'll get our first taste of that 11% ramp soon...

Here's what the riders have to expect - a Madonna-on-her-back-circa-1990 of a profile, with that pointy climb up to the cathedral of Notre Dame the big challenge on an otherwise flat and fast course.

Yesterday, justice was finally done when Edvald Boasson Hagen soloed to a magnificent Stage 19 win in Salons-de-Provence - attacking from a break to turn his four winless podium finishes to a victory, as Chris Froome edged closer to a fourth Tour de France title after finishing safely in the pack.